The objective is to delineate, as fully as possible, the role and function of coca in traditional Bolivian culture. It will include a basic ethnography of the traditional and changing patterns of coca use in Bolivia, will place these patterns in historical perspective, and will initiate some bio-medical exploration through testing for cocaine blood levels resulting from chewing a known quantity of the leaf. The research will build upon an initial study of the commercialization and distribution of coca through traditional channels. This study is beginning in July, 1976, and is being funded through USAID as part of a coca crop substitution effort. Timing for the research is urgent. The government of the United States and of Bolivia have agreed to attempt a major program of coca rationalization. Their hope is to reduce coca production to the point that sufficient supply remain for traditional use, medical use, and legal export, but to curtail completely the supplies of the leaf going into cocaine. These goals can never be met without a full understanding of the patterns of traditional use. This research is intended to delineate that use, and to assess the impact any tampering with the system may have on the mental and physical health, belief systems, and social cohesion of traditional Bolivian populations.